Summary [AniDB]: Macross Delta is set in the year 2067, 8 years after the events of the latest Macross TV series, Macross Frontier. The story focuses on Walküre, a team of talented idols and Valkyrie pilots and the Delta Squadron, a team of experienced Valkyrie pilots as they battle against the Var Syndrome, a mysterious entity that is consuming the galaxy. But both must battle the mysterious Aerial Knights, a group of Valkyrie pilots from the Kingdom of Wind.
Source : Wiki